P0573
OBD-II Diagnostic Code
Severity: MinorWhat it means
P0573 means the brake pedal switch circuit is sending a high signal to the ECM.
This affects cruise control (it may not engage) and can affect brake lights.
The brake light switch on the brake pedal is the usual cause.
Affected Models
- All OBD-II vehicles (1996+)
Common Causes
- Brake light switch stuck or misadjusted
- Brake light switch wiring issue
- Brake pedal not returning fully
- ECM input circuit fault
How to Fix It
-
Check if brake lights are stuck on or not working.
Have someone watch the brake lights while you press and release the pedal.
Stuck-on brake lights confirm a switch problem. -
Adjust or replace the brake light switch.
The switch is on the brake pedal arm under the dashboard.
It is a $10-$30 part and usually clips in — no tools needed. -
Check that the brake pedal returns fully when released.
A sagging pedal may not release the switch fully.
Check the pedal return spring.
Frequently Asked Questions
Can P0573 drain my battery?
Yes.
If the brake lights are stuck on due to a faulty switch, they will drain the battery when the car is parked.
Will cruise control work with P0573?
Usually not.
The cruise control system disengages when it sees a brake signal, and P0573 means that signal is always high.